ES2532995T3 - Controllers arrangement of an electric power transfer system of a wind turbine - Google Patents

Abstract

A system comprising a wind turbine, an electric generator, an electric power transfer system (1) and an electric supply network, in which the power transfer system (1) is arranged to transfer electric power from the generator to an electricity supply network; wherein the power transfer system (1) comprises at least two electrical elements (2-6) and at least two controllers (15-17), each arranged to control at least one element (2-6); wherein at least one controller (15-17) is arranged to control only one of the elements (2-6) as well as at least two of the elements (2-6); and the arrangement of controllers allows a first element (2-6) to be controlled by a first controller (15-17) and a second element (2-6) to be controlled by a second controller (15-17), as well as the first and the second element (2-6) are controlled by the first controller (15-17) while the first or the second element (2-6) is not controlled by the second controller (15-17).

Description

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DESCRIPTION

Controllers arrangement of an electric power transfer system of a wind turbine

The invention relates to the field of wind energy conversion and, for example, to a system comprising a wind turbine, an electric generator, an electric power transfer system, and an electric supply network.

Background

EP 2 161 443 A2 describes a wind turbine with a generator and a power transfer system for supplying electrical power to a distribution network. The power transfer system has a master controller and two power converters, a main converter and an auxiliary converter, each of the

10 which includes properly adapted slave controllers. In an emergency, the controller (formerly slave) of the auxiliary converter functions as an independent master to regulate the flow of power to an internal supply network.

The EP document describes, in relation to an electric generator, a dynamic brake and a lever circuit, designed to cooperate with power converters to discharge power after an order.

15 Summary of the invention

A system comprising a wind turbine, an electric generator, an electric power transfer system, and an electrical supply network is provided. The power transfer system is arranged to transfer electrical power from the generator to the power supply network. The power transfer system comprises at least two electrical elements and at least two controllers each arranged to control the

20 minus one element, in which at least one controller is arranged to control only one of the elements as well as at least two of the elements. The arrangement of controllers allows a first element to be controlled by a first controller and a second element to be controlled by a second controller, as well as the first and second elements to be controlled by the first controller while the first or second element It is not controlled by the second controller.

According to another aspect, a control procedure of an arrangement of controllers of an electric power transfer system of a wind turbine is provided. The wind turbine comprises an electric generator and is connected to a power supply network. The power transfer system is arranged to transfer electrical power from the generator to the power supply network. In addition, the power transfer system comprises at least two elements and at least two controllers each arranged to control the

30 minus one element, in which at least one controller is arranged to control only one of the elements as well as at least two of the elements. The method comprises: switching between 1) controlling a first element with a first controller and a second element with a second controller and 2) controlling the first and second element with the first controller while the first or second element is not controlled with the Second controller

35 Other features are inherent in the products and procedures disclosed or will be apparent to those skilled in the art of the following description and the accompanying drawings.

Brief description of the drawings

The embodiments of the present invention are explained by way of example with reference to the attached drawings, in which:

40 fig. 1 is a schematic drawing of an arrangement of a power transfer system with a focus on system elements,

fig. 2 is a schematic drawing of a power transfer arrangement with a focus on system controllers,

fig. 3a and 3b are schematic drawings of two power paths of the power transfer system 45 showing the distribution of the controllers,

fig. 3c is a schematic drawing of handover stages, and

fig. 4 is a schematic diagram showing the communication of the controllers.

The drawings and the description of the drawings are embodiments of the invention and not of the invention itself.

Detailed description

50 The embodiments refer to a controller arrangement of a power transfer system

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of a wind turbine and a procedure for its control. The wind turbine produces electrical power by operating the generator with a wind turbine rotor. The generated power is transferred by the power transfer system of the generator to a power supply network, for example a public network connected to the wind turbine. For this functionality, the transfer system comprises electrical elements, for example

5 a power converter, power components (e.g. filters, circuit breakers / contacts, etc.) and / or a transformer, and controllers to control the elements. The generator and the network are at least one source and one electric power charge, respectively.

The distribution of controllers is facilitated by at least one first controller that is arranged to control only one of the elements as well as at least two of them. Thus, it is possible to switch between at least 10 two modes of operation: 1) control a first element with the first controller and (independently control) a second element with a second controller (hereinafter referred to as "independent" mode). And, to obey the distribution, 2) control the first and the second element with the first controller while the first or the second element is not controlled with the second controller (hereinafter referred to as "distribution mode"). In the distribution mode, the second element (which was controlled

15 previously by the second controller, according to the independent mode) is now controlled by the first controller, while the first controller controls (still) the first element. Thus, the first controller is distributed to control both the first and the second element. The distribution of the controller can improve the performance and / or reliability of the power transfer system and / or provide redundancy.

Before returning to the detailed description of the embodiments based on the drawings, about 20 few more general elements of embodiments will be analyzed.

In some of the embodiments, the independent mode is a normal operating mode of the wind turbine. In the following, the term "normal mode" describes a mode of operation, in which the wind turbine is producing electrical power while the power transfer system is working without failures. In some embodiments, the distribution mode is a normal wind turbine mode. As the first

25 controller controls the second element in the distribution mode, the second controller can be turned off, thus increasing the life and power availability of the turbine to the network. In some implementations, the power transfer system is arranged to operate in both modes, independent and distribution mode, as normal modes.

In some embodiments, switching between the at least two modes of operation (mode

30 independent and distribution) is triggered by a fault condition. However, it should be noted that switching between the at least two modes can also be triggered by any other condition related to the performance improvement of the power transfer system in other embodiments. In one implementation, the operating mode switches from the independent mode to the distribution mode in response to the fault condition, thereby canceling the control of the second element by the second controller. (So

35 then, the distribution mode is not a normal mode). Therefore, the second controller is no longer necessary to control the second element and a failure caused by the second controller will not affect the good state of the power transfer system. Additional embodiments, related to the cooperation of the elements and controllers, are described below.

In some embodiments, the elements are associated with controllers, for example the number of

40 controllers is the same as the number of elements controlled by these controllers, or, alternatively, the number of controlled elements is twice the number of corresponding controllers.

Before describing more details regarding the operation and distribution of controllers, a few more aspects of the power transfer system will be discussed.

In some embodiments, the generator is a single power source, for example from a power source.

45 AC power. In other embodiments, the generator provides at least two power sources, for example each of an AC power source. In some implementations, the generator provides at least one single phase AC power source. In some other implementations, the generator provides at least one of a multiphase AC power source, for example, a three phase AC power source.

In one implementation, the generator can be divided into a plurality of generator segments, which produce a plurality of independent AC power outputs and therefore represent separate power sources. Segmented generators increase the reliability of a generator as well as the availability of power, since generator failure events mainly affect only isolated generator segments, so that the other segments can continue to operate.

55 In some embodiments, the power supply network is a single power load. In other embodiments, the power supply network is at least two power loads. In some implementations, the network provides at least one single phase AC power load. In some other implementations, the network provides at least one of a multiphase AC power load, for example, an AC power load

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three phase.

The power transfer system couples the at least one power source to the at least one load by providing at least one power path between the at least one source and the at least one load. Since the power generated by the generator depends on the rotational speed of the wind turbine rotor (for example,

5 can be affected the frequency, amplitude and / or phase of the AC voltage output), the power transfer system converts, in an example, AC power of the wind turbine generator into AC power that satisfies the requirements of the network or of the wind farm operator and, finally, supplies the power to the network. More details of this are described below.

In some embodiments, at least two of the elements are electric power converters and at least

10 two of the controllers are converter controllers. Each of the converter controllers is arranged to control at least one converter. At least one of the converter controllers is arranged to control one as well as two converters.

In one embodiment, for example if the transfer system couples a single power source to a common load, the converters can be controlled electrically in parallel providing different

15 power paths. In other examples, the converters may not be connected to their inputs or outputs or both, for example if the converters are coupled to different power sources or to different loads or to both. If a galvanic coupling is provided only on one side of the converters or not provided at all, it is possible to avoid or at least limit a cross-current flow from one converter to the other.

Providing a plurality of converters in parallel allows the current to be redistributed, with the result of

20 that flows less currents through the individual converters. In addition, implementations with plural converters (not necessarily strictly in parallel) can improve the reliability and availability of the power conversion system and provide redundancy. For example, each converter may comprise or be connected with controllable switches to isolate, and thus deactivate, individual converters of the at least one power source and / or the at least one load. In addition, they can be coupled at least

25 two converters by means of controllable switches to allow the derivation of the deactivated converters. Thus, in some examples it may be possible to distribute all or part of the otherwise routed power through the deactivated converter to one or more of the other converters or elements of the transfer system. In other implementations that connect the converters to dedicated power sources, for example dedicated generator segments, the transfer system can continue to operate with a

30 power delivered reduced if one of the converters is deactivated.

According to some embodiments, the power transfer system comprises at least one AC / DC converter as an element, which is arranged, for example, to provide converted DC power from an AC source or generator. In some implementations, the AC / DC converter comprises a passive rectifier or an active rectifier, for example a phase controlled rectifier with power switches.

35 semiconductor controlled by the converter controller.

In some embodiments, the power transfer system comprises at least one DC / AC converter as an element, which is arranged, for example, to provide converted AC power from a DC source, ie the generator power. in the CC link. In some implementations, the DC / AC converter comprises semiconductor switches controlled by the converter controller. Commuting

Suitably semiconductor switches with pulse width modulation (PWM) signals achieve an (essentially) sinusoidal output waveform at the terminals of the converter to supply the power demanded at the load site.

In some embodiments, the power transfer system comprises at least one DC link arranged to couple at least one AC / DC converter and at least one DC / AC converter. In some 45 implementations, at least one frequency converter of the power transfer system is constructed by at least one AC / DC converter on the source side and at least one DC / AC converter on the load side coupled by the minus a CC link. In the following, the expression "source side" denotes that an element is closer to the source than to a reference element. The expression "load side" denotes that an element is closer to the load than the reference element. In some implementations, the frequency converter is arranged to convert / transfer electrical power at the AC source or the generator to AC power demanded by the load or network by adapting the frequencies, amplitudes and / or AC phases. For example, the converter controller synchronizes the phase frequency with the mains AC voltage and regulates the amplitude and phase of the AC voltage produced by the power converter to a suitable value to supply the power demanded in the network. . In some implementations, the necessary information regarding frequency,

The phase and amplitude of the source side and the load side is provided by at least one source-load management controller, described below.

In some embodiments, a frequency converter is an element of the transfer system, so the converter controller is a frequency converter controller that is arranged to control various components of this element, for example the AC / DC converter , the DC / AC converter and the link

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of intermediate DC, all members of the frequency converter being an element.

In one example, at least two DC links can be coupled via controllable switches. This may allow the derivation of the converters, for example a DC / AC converter on the load side or an AC / DC converter on the source side. In addition, connecting the DC links can improve the balance of

5 DC link voltage of different power paths.

In addition, the transfer system may comprise at least one controllable switch to isolate at least one AC / DC converter from the source side and / or at least one DC / AC converter from the load side of at least one source of power and at least one load, respectively.

In some embodiments, at least two of the elements are power dissipation units and at

10 minus two of the controllers are power dissipation unit controllers. The number of dissipation units may be the same as the number of converters or DC links or half of the number of converters, for example one power dissipation unit per frequency converter.

Each dissipation unit may comprise one or more dissipation components that can convert the electrical power to be dissipated into heat or a different form of energy, for example one or more

15 resistors In one example, the amount and / or speed of power dissipation can be controlled, for example by means of PWM signals that control corresponding switches.

In the following, the expression "power to be dissipated" refers to a power present in a power path of the power transfer system that cannot be properly managed by the converters or by any other system element due to a failure event of some kind. For example, the dissipation unit is arranged to dissipate the power that is introduced to a converter from the at least one power source, but cannot be converted / transferred due to a converter failure; or an excess power input to a converter, because the wind turbine rotor connected to the generator representing the at least one power source is accelerated, thus producing more power; or residual power on the DC link after deactivation of a converter. Thus, the at least one dissipation unit can be

25 coupling with at least one power path of the transfer system, for example with at least one converter and / or with at least one DC link. Dispelling such power can protect electronic components of the system and thus prolong its life.

In some embodiments, the power dissipation unit is coupled to the power path by means of one or more controllable switches. In some alternative embodiments, in particular if the

The amount of power dissipation can be controlled and the dissipation does not start automatically as soon as power is available as input to the dissipation unit, the dissipation unit can be permanently coupled to the power path, especially to the converter, without using switches

According to some embodiments, the at least two dissipation units are coupled (to each other) by means of controllable switches. On the one hand, this allows the power to be dissipated to be distributed to at least two two dissipation units, thus allowing greater amounts of power to be dissipated without providing larger dissipation units and protecting the separate dissipation units from overload or wear, for example during long-term failure events. On the other hand, the dissipation units can be coupled to allow the derivation, in an example, of a dissipation unit (for example with failures), thus providing redundancy. In some embodiments, all dissipation units can be coupled to each other by means of lines

40 which are interrupted by the controllable switches.

In some embodiments, for example if the input power is a multiphase AC power provided by multiple phase lines, the dissipation units may comprise a number of dissipation components (eg, resistors) that is equal to the number of phases (phase lines) of the input power. In the event that the multiphase AC input power is going to dissipate, each component

45 dissipation can be coupled to a corresponding phase line. Alternatively, the dissipation unit may comprise an AC / DC converter, for example an active / passive rectifier, to convert AC power to DC power; The DC power can then be dissipated by a single power dissipation component. The only power dissipation component may be a bank of power dissipation elements.

In some implementations, the at least one controllable switch in some embodiments is controlled by at least one controller. For example, it is controlled by a controller that controls an element adjacent to or associated with the switch, for example the power dissipation unit controller or the converter controller. In some embodiments, the switch is a logical or physical part of the element. In some embodiments, the switch is an (separate) element of the transfer system

55 of power with at least one switch controller arranged to control only one as well as at least two switches. Alternatively, the switch can be controlled by an electronic device that automatically provides connection under certain predetermined conditions (for example, diodes that are activated at a predetermined voltage drop).

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In some embodiments, at least one of the generator and the network provide as elements at least two sources and loads, respectively. At least two of the controllers are source-load management controllers, each arranged to monitor at least one of the source and the load. Additional tasks of this type of controller are described below.

5 Generally, the aspects of controller distribution should be understood as applicable to any type of controller described before and in what follows.

Returning again to additional details of the controllers, in some embodiments a controller of a specific type is arranged to communicate with a controller of a different type. For example, the power transfer system comprises at least one converter controller, at least one converter

10 electrical power and at least one controller of the power dissipation unit, in which the converter controller is arranged to provide at least one of information about itself and information about the power converter to the controller of the dissipation unit of power (note: this embodiment comprises at least one more element).

In some embodiments, the controllers are arranged to meet a single task or combination.

15 of various tasks, for example tasks listed in the following three paragraphs. In some implementations, controllers of the same type satisfy the same task coverage. In some implementations, controllers of the same type can be freely exchanged in relation to the control of any element of the same type and / or replace physical devices representing the controllers.

In some examples, at least one source-load management controller is provided to manage at least one

20 of the following tasks: monitor the status of at least one source and / or at least one load; provide event information to other controllers, for example source status and error, load status and error, status of the source-load management controller and error; provide system commands, for example start, stop, generate power; provide an information signal (especially in real time), for example about desired power set points of the individual converter, available source power and / or consumption

25 load power.

In some examples, at least one converter controller is arranged to manage at least one of the following tasks: monitor and / or control adjacent converters and / or switches; establish a healthy transfer system and / or optimize power performance based on available wind through cooperation with other controllers; provide event information to other controllers, for example status

30 of the converter and error, status of the controller of the converter and error; provide an information signal (especially in real time), for example about the power flow of the converter, energy stored in the power path, in the converter and / or in the DC link.

In some examples, at least one controller of the power dissipation unit is arranged to manage at least one of the following tasks: monitor and / or control power dissipation units; optimize the

35 power balance between different power paths, especially with regard to different generator segments; provide event information to other controllers, for example power and error dissipation unit status, power and error dissipation unit controller status; provide an information signal (especially in real time), for example about the dissipated power and / or the state of good functioning of the power dissipation unit.

In some embodiments, at least one controller materializes as a physical device. For example, the controller comprises at least one microcontroller. For maintenance purposes, all or at least two controllers are built as separate (physical) devices in some implementations. Alternatively, at least two controllers are integrated into a single (physical) device, for example some or all controllers related to the same power path and / or some or all controllers of the same type are

45 can be integrated as modules in a physical device.

In some embodiments, at least one controller is embodied as a logical unit, for example as a logical part of a common physical device or as a logical part of a program arranged to be executed by a computer. In some examples, some or all controllers relating the same power path and / or some or all controllers of the same type or at least two of any of the controllers

50 are implemented as logical units (separate).

In some embodiments, at least one controller materializes as or with a process arranged to be executed in a controller program or as an instance of a generic controller program executed by a computer. In some implementations, the controller program comprises various processes, each of which represents an individual controller. In some implementations, various controllers materialize through various instances of a controller program, each instance representing an individual controller. In some other implementations, all controllers related to a specific power path or all controllers of the same type are materialized in common by a single processor

or by a single instance of a controller program.

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Communication between controllers materializes, for example, by means of at least one physical communication link, a shared memory and communication between processes.

In some implementations, the information provided by a controller is shared with at least one adjoining controller, with at least all controllers of the same type, with at least all controllers 5 related to the same power path, with all system controllers. of power transfer, and / or with the main controller of the wind turbine.

In some embodiments, at least the first controller is arranged to control at least two elements in unison. In this case, the controller treats these elements in the same way and does not distinguish between them. In some examples, the controller does not have to know how many elements it is controlling. In some implementations the

At least two elements are connected, for example physically or logically, to the controller in parallel, for example by switches or by means of a shared memory. Thus, each control command generated by the controller can be transmitted (simultaneously) to the controlled elements. In some implementations, the at least two elements are connected in series in a chain. Thus, a specific control command is delivered from a preceding member of the chain to a subsequent member of the chain.

In some other embodiments, at least the first controller is arranged to control (essentially) at least two elements independently. In this case, each of these controllers is arranged to distinguish between at least two elements, for example by providing different control commands and / or different timing of the control commands for different elements. In some implementations, at least one controller is arranged to behave like at least two independent controllers, each controlling the

20 minus one element separately.

In some embodiments, a control command comprises a complex task, for example converting a specific power or synchronizing voltage phases on the source side and / or on the load side. In some implementations, the control command comprises at least one parameter, for example a value of an AC voltage amplitude. Such control commands are interpreted by an element microcontroller or by a process

25 representing the controller, in some implementations.

In some other embodiments, a control command is arranged to directly trigger a physical or process equipment, for example, an electrical signal to control a semiconductor switch, an electrical signal to trigger a microcontroller or specific value in a shared memory.

In some embodiments, at least the second controller is arranged to generate a signal intended for

At least the first controller to provide at least one information about itself and information about at least one of the elements controlled by it. In some implementations, address information is encapsulated in the signal to be sent to at least one specific controller, for example to be sent to a specific controller, a group of controllers of the same type or controllers related to the same power path. This allows direct communication between at least two controllers.

In some embodiments, at least the second controller is arranged to generate a broadcast signal to provide at least one information about itself and information about at least one of the elements controlled by it. In this case, the controller provides (easily) information to all controllers who listen to those broadcasts, especially without having to know anything about the controllers they are listening to.

40 In some embodiments, a controller that receives the signal from another controller decides whether or not to ignore the signal information. Thus, a broadcast signal can be sent even to controllers that do not need the signal. So the sending controller does not need to make an effort to address correctly. In some implementations, controllers organize and communicate without a master-slave structure. In some examples, a distributed controller system is materialized with reception controllers that

45 react (only) to signals that concern them.

In some embodiments, at least two controllers are arranged to support a synchronous exchange of information. For example, the first controller is arranged to require information from the second controller, which is arranged to provide this information upon request.

In the same or in alternative embodiments, at least two controllers are arranged to support a

50 asynchronous information exchange. For example, the second controller is arranged to send information without being asked, for example at fixed time intervals, as soon as new information is available and / or as soon as a value changes in more than a specified threshold.

In some embodiments, all or at least two controllers interact with a main controller, for example a main wind turbine controller, see the following. This main controller can be distinguished from the (other) drivers described so far. In some implementations, the main controller is arranged to function as a master for the (other) controllers, which are thus arranged to function

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Like slaves. Thus, the main controller can manage the distribution of controllers.

In some other embodiments, at least the first controller is arranged to decide in an isolated manner whether to control only one element or control at least two elements at the same time. Thus, the main controller does not need driver distribution. In some implementations, the controllers are arranged to act

5 as a self organized network. For example, if a failure of the second controller occurs, the first controller can assume the tasks of the second controller autonomously, for example by finding a decision based on status or error information sent by the second controller or based on the fact that the Second controller no longer sends signals.

In some embodiments, the generator and the network provide at least one source and one load

10 respectively. The power transfer system comprises at least two electric power converters and at least one power dissipation unit as elements, at least two converter controllers, at least one dissipation unit controller and a power path arranged to transfer electric power to the load. The method comprises: controlling a first converter with a first converter controller and a second converter with a second converter controller being both

15 converters connected to the power path (here, this is the normal mode described above). In response to a fault state caused by the second controller: disconnect the second converter from the power path and connect the power channel to the power dissipation unit controlled by the power dissipation unit controller; transfer the second converter to the first controller of the converter; disconnect the second converter from the power dissipation unit and reconnect the second

20 converter to the power path.

In this embodiment, the second converter is transferred to the first controller of the converter, for example if the second controller fails. The second converter can be disconnected as soon as possible from the power path and connected to the power dissipation unit, for example to minimize the spread of the fault further in the system and / or to protect power and electronic components of the system. Then,

The transfer takes place, that is, the controller of the first converter (without failures) assumes control over the second converter. Thus, the first controller of the converter is distributed to control both converters, the first and the second. Finally, the controller of the second converter (with failures) no longer needs to control the second converter (and can be reset or replaced).

In some embodiments, the transfer of control of an element is initiated by the second controller, it is

30 say, the controller that controls the element before handover. In some implementations, the second controller communicates a request for transfer of control to a specific (first) controller. In some other implementations, the second controller communicates such a request to at least two controllers, for example to all controllers of the same type or to all controllers associated with the same power path. To send this request, the controller can use any type of communication, signal or information described above.

35 or in what follows.

In some embodiments, the transfer of an element for control is initiated by the first controller, that is, the controller that controls the element after the transfer. In some implementations, the first controller communicates a request for transfer of control to the second controller. In some other implementations, the first controller transfers control without a request, for example, if the second controller has failed and is not capable

40 to receive a request or to communicate.

In some embodiments, the handover is carried out by switching an information line, that is, by cutting a line for control commands between the second controller and the element to be controlled and establishing a line for control commands between The first controller and the element. This cutting and establishment are carried out by switching some physical signal lines that connect the

45 controllers and the element through semiconductor switches, in some implementation. In some other implementations, this is achieved by changing programming or shared memory parameters, for example by changing some pointers that point to a shared memory or a process that represents the element.

In addition to the controllers described here, in some embodiments the wind turbine comprises the main controller of the wind turbine for different types of tasks. For example, the wind turbine controller 50 determines whether the wind turbine should operate, at the current wind speed, in a partial load mode (in which the efficiency of energy conversion is optimized) or in a mode of nominal load (in which the nominal power is produced, even if the wind speed allowed for greater power production). In addition to mechanical operating parameters, such as rotor speed and blade pitch, the wind turbine controller controls parameters for total delivered electrical power. The control of the

55 Electric power delivered is done by influencing the power transfer system of the wind turbine.

The wind turbine can be integrated into a wind farm that combines a plurality of wind turbines connected by an electricity supply network through a main transformer. Each wind turbine supplies the electric power produced by it to the electricity supply network. There may be a wind farm controller that influences the power delivery of the wind turbine.

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Fig. 1: arrangement of the power transfer system in relation to the elements

An embodiment of the power transfer system 1 that is arranged to transfer electrical power from AC sources 2 to AC loads 3 is shown in fig. 1 as a schematic drawing. The power transfer system 1 part of a wind turbine with an electric generator that provides sources 1 and is

5 powered by a wind turbine rotor. The wind turbine is connected to an electrical supply network that provides the loads 3. Neither the generator nor the network are part of the power transfer system 1. In this example, the sources 2 and the loads 3 are physically connecting elements of power that connect system 1 with the generator and the network, respectively.

In fig. 1, the generator comprises four generator segments, which can be treated as four outputs of

10 independent AC power. Thus, in fig. 1 the individual symbol 2 must be understood as four sources 2, as shown by the four connection symbols. For example, the generator segments are sets of windings isolated from the wind turbine generator, which produce respective three-phase AC power outputs. Such generator segments are often arranged in symmetrical pairs (for example, in pairs of arranged windings distributed symmetrically axially along the stator).

The network can be treated as four 3-phase AC loads 3, for example transformers connected with their secondary windings to the power supply network, represented by the four connection symbols of the individual symbol 3. Thus, all sources 2 and loads 3 are arranged for three-phase AC power, where the power transfer system 1 feeds the loads 3 by converting the AC power of the sources 2 to meet the requirements of the loads 3 , as described in the following.

In addition, the system 1 comprises four AC / DC converters (three phase) 4, four DC / AC converters (three phase) 5 and four power dissipation units 6 as elements. For example, AC / DC converters 4 are generator side converters and DC / AC converters 5 are network side converters of power transfer system 1, connected via DC links. In other examples, system 1 comprises more or less than four of these elements 3-6 and / or sources 2 and loads 3. In some examples, the

25 number of power dissipation units 6 is the same or half of the number of converters 4 and 5. In some examples, the number of each of the elements 3-6 is a multiple of the number of AC phases provided by the sources 2 and / or loads 3.

As shown schematically in fig. 1, source 2 and load 3 are logically grouped in a first (internal) channel, converters 4, 5 in a second (intermediate) channel and power dissipation units 6 in a

30 third channel (external). The external and intermediate channels have some DC 7 links in common, just as the intermediate and internal channels have some AC 8 links in common, represented by lines in fig. one.

To transfer the AC power from the sources 2 to the loads 3, the system 1 provides various power paths, that is, power paths along the elements 2-6 and the AC and DC links 8, 7. The electric power flow can be guided by controllable switches 9-14 located along the paths

35 power between items 2-6.

Switches 9-14 as well as all other controllable switches mentioned above and below can be any device that allows breaking down and establishing a controllable connection depending on control signals of a controller. For example, the switches can be circuit breakers, contacts with or without a fuse, semiconductor power switches, for example 40-door isolated bipolar transistors (IGBT), metal oxide semiconductor field effect transistors (MOS-FETs), thyristors Door deactivation (GTO), anti-parallel thyristors or controllable diodes. A controllable switch may comprise one or more switches. For example, a controllable switch to break and establish a three-phase line may comprise three switches, one for each phase line. In another example, a controllable switch comprises redundant switches, for example two parallel switches, which allows

45 Selectively establish and break the corresponding connection even if one of the switches is damaged. Here, the expression "close" a switch designates controlling the switch to make a connection; the expression "open" a switch designates controlling the switch to break a connection.

Next, the arrangement will be described by the following power flow. Starting at sources 2, each source is individually connectable to an associated AC link 8 by closing an associated source switch 9 50. This AC link 8 is directly connectable to an associated AC / DC converter 4 by closing a converter switch 11 on the associated AC side. (For better exposure, Fig. 1 shows only one of the corresponding reference signs 7-14). Alternatively or in addition to, the power flow can be redirected or divided by AC link switches 10, each of which connects two AC links 8. Opposite to each AC link 8, a converter switch 12 of the DC side to each

55 converter 4, with switch 12 arranged to connect or disconnect the associated converter 4 and AC link 7. In addition, each DC link 7 can be coupled with at least one adjacent DC link 7 via DC link switches 13 .

So far, the power has reached the DC 7 links. In general, the DC 7 link may comprise a

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capacitive energy storage (for example, a capacitor), or, especially when only low currents take place, an inductive energy storage (for example, an inductor).

From here, the power can be guided to a load 3 passing through at least one DC / AC converter 5 in the opposite direction to what was described above, according to the AC / DC converter 4, in which the loads 5 3 are individually connectable to adjacent AC links 8 via 9 'load switches. Alternatively or additionally, part or all of the power on the DC link 7 and / or from one or more adjacent controllers 4, 5 can be dissipated with a power dissipation unit 6 by closing a switch 14 of the power dissipation unit . For example, this may be useful in the case of a converter failure, a fault of the sources 2 or loads 3, especially to ensure symmetrical voltage of symmetrical segments of the generator

10 segmented, in the case of an imbalance of sources 2 and loads 3 and in the case of a transient, for example when switching power paths, in an alternation of the load, starting or switching off a source 2 and / or a load 3.

Each of the power dissipation units 6 can comprise a resistance in series with the switch 14. The amount and speed of the power dissipation can be controlled by varying duty cycles of 15 a pulse width modulation operation (PWM) of the switch (of power electronics) 14 in series with the resistor. The power dissipation can be increased by connecting at least one additional power dissipation unit 6 by closing at least one DC link switch 13 to couple adjacent DC links 7. In other examples, a power dissipation unit can be connected to an AC link. For example, such a power dissipation unit may comprise a plurality of resistors, each resistance

20 connectable to a separate AC phase.

The arrangement of the power transfer system 1 allows various connection combinations at least one AC / DC controller 4 with at least one DC / AC controller 5 using at least one DC link 7. These combinations construct at least one power converter. frequency, which is connected to source 2 and load 3 through at least two AC links 8. Such a frequency converter can be configured (freely) to involve one or more individual AC / DC 4 converters and / or one or more individual DC / AC converters 5, where the numbers of different converters 4 and 5 may be the same or different. Thus, the (maximum) power flow of the frequency converters so constructed can be configured (upon request) while the system is operating.

one.

Fig. 2: Power transfer system arrangement in relation to controllers

30 Fig. 2 shows the same system 1 as fig. 1, but as a schematic circuit diagram of controllers 15-17. The controller arrangement supports independent controller functionality as well as shared controller functionality, for example in the event that one or more controllers are damaged or during transient events, for example when the functionality of the existing controller is assumed by an adjoining controller.

As the comparison of figs. 1 and 2, each of the elements 2-6 shown in fig. 1 is associated with

35 a controller 15-17 shown in fig. 2: source-load management controllers 15 are associated with the internal channel and with sources 2 and loads 3, respectively; Controllers of converter 16 are associated with the intermediate channel and with converters 4, 5 and controllers 17 of the power dissipation unit are associated with the external channel and with the power dissipation units 6.

In addition to this association, each controller 15-17 is arranged to control a second element 2-6 in addition to

40 its associated element. Thus, all controllers 15-17 are arranged to control only one individual 2-6 element (the associated one) as well as to control two elements at the same time, that is, the associated (first) element 2-6 and one (second ) Additional element 2-6 associated with another controller 15-17 (of the same type). For example, when operating system 1, at one time a specific converter 15 controller can control (only) the associated converter 4, at another time the same controller 15 can control both, the associated converter 4

45 and a second converter 4 of the same type. In another example, the controller 16 is arranged to control two elements 4, 5 of different types, that is, an AC / DC converter 4 and a DC / AC converter 5, at the same time.

Before describing more details of the distribution of the controller, some general aspects will be mentioned first.

Controllers 15, 16 and 17 are arranged to monitor the status of associated elements 2-6 to pass

50 information about each other regarding the state of proper functioning of system 1 and other information relevant to the optimized and self-organized operation of system 1.

The source-load management controllers 15 are arranged to monitor the status of the sources 2 and loads 3. In addition, the source-load management controllers 15 control the source switches 9 and the load switches 9 'to connect ( and disconnect) individually 2 sources and 3 individual loads. By

For example, in the case of excessive system load 1 or in a generator failure state, at least one source 1 can be disconnected; in other cases, the network or a subnet of the network can be disconnected from system 1.

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The controllers of the converter 16 are arranged to monitor and control the proper functioning of the converters 4, 5. They have the main function of establishing a good operation of the converter and optimizing the power flow through each of the converters 4, 5 and Moreover, the total power flow produced by the generator to the grid based on the available wind. In addition, the controllers of the converter are arranged 5 to control the switches 11, 12 of the converter adjacent to the converters 4, 5, thus controlling whether the converters 4, 5 connect or not to the DC links 7 or the AC links 8 In addition, the controllers 16 directly control the switching semiconductors of the converter, that is, semiconductors of an AC / DC converter rectifier 4 and / or switching semiconductors of an inverter of the DC / AC converter 5, respectively. Thus, they control the power supply to the DC 7 link (for example, the voltage

10 dc and / or dc current) and / or the power (eg frequency, amplitude, phase) supplied to the AC link 8.

The controllers 17 of the power dissipation unit are arranged to monitor and control the proper functioning of the power dissipation units 6 and to optimize the power balance of the system 1 as a whole, especially between connected power paths (by means of different sources) to different generator segments. The controllers 17 control whether the units 6 connect or not to the DC links 7.

In addition, they control the amount of power dissipated by directly controlling the switches 14 with PWM signals. Additional tasks of the different types of controllers are described in fig. Four.

In other examples, controllers 16 and 17 do not directly control switching semiconductors of elements 4, 5 and 6. They control the elements by providing control commands and / or setpoints, for example for reference of power, voltages and / or current AC or DC, frequency, amplitude and phase of an AC signal,

20 PWM frequency and / or on / off speed. In that case, elements 16 and 17 are more "intelligent", for example they have a microcontroller arranged to satisfy these requirements autonomously.

In one embodiment, each of the controllers 15-17 is represented by a process that is part of a common controller program that is executed by a wind turbine computer. Each process is associated with some input and / or output ports (I / O ports) of the computer that are also parts of the controller. Thus, the controller is implemented by a combination of equipment and program. (Alternatively, I / O ports can be assigned to the elements, so the controller is created only programmatically). In this embodiment, the controllers communicate (see Fig. 4) using a shared memory that is accessible by all controller processes and through communication between

30 processes Elements 2-6 are electrically connected to the I / O ports to establish communication between controller and controlled element.

In another embodiment, each controller is represented by a single physical device, each of which has a microcontroller to control the at least one element and for communication with other controllers. All elements that are controllable in principle by a specific controller are connectable

35 electrically to this controller via signal lines 18 and switches. In addition, the controllers are connected to each other via communication lines 19, for example by a common data bus or by individual signal lines, each connecting two controllers (see Figs. 3a, 3b).

Now, returning to the distribution of controllers, the arrangement of controllers allows a first element to be controlled by a first controller and a second element is controlled by a second controller

40 (independent mode), as well as controlling both the first and the second element by the first controller while the first or the second element is not controlled by the second controller (shared mode). The 15-17 controllers are organized as a network that builds a distributed system. They are connected to each other via communication lines 19.

In an independent mode, a controller actively controls an individual (associated) element. So, (others)

45 contiguous elements can be controlled by (other) contiguous controllers. In addition to this, shared control functionality is the state in which a controller assumes functional responsibility for an element that was governed (formerly) by another active controller. The shared mode can limit the effects of faults or increase the flow of power to the load.

In one embodiment, in shared mode, a controller controls two contiguous elements in unison, by

50 example by specular control of the I / O ports or by connecting corresponding signal lines between controller and controlled element.

In an alternative embodiment, in shared mode, a controller controls two contiguous elements independently. In this embodiment, each of the controllers is equipped with two independent control units, one unit that controls the first associated element and the other unit that controls the

55 second item. In the independent mode, only one of these units is active, since the other can be at rest and can be designated as backup, thus increasing redundancy. For example, these units are separate threads from the controller process.

However, all 15-17 controllers act as an independent controller managing only

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its controlled element (s) based on the knowledge of which controllers control contiguous elements themselves. In addition, the control is based on inputs from other controllers present on it and on other channels. Thus, each controller decides in an isolated way whether to control only one element or two elements at the same time; there is no master who assigns a specific element to a specific controller. Deciding in an isolated way 5 means that the controller makes its own decision based on its knowledge about the other elements and controllers and its own state. The transfer of one element from another (second) controller can be initiated by the other (second) controller upon request, for example if the second controller identifies an internal fault by itself. In addition, the handover can be initiated by the (first) controller that takes control of the element, for example, if the first controller discovers a failure of the second controller, for example by actively observing and / or

10 analyzing the information received about contiguous elements and controllers. Even the fact that the second controller (with failures) no longer sends any information can be used to initiate a transfer (takeover) of the element associated with the second controller.

Fig. 3a-c: handover

The handover is explained by the following example. Fig. 3a schematically shows a part of system 1

15 with two power paths (by continuous line) before handover. Fig. 3b shows the same part after the transfer. The signal lines 18 are drawn as continuous arrows, while the directions of the arrows show the "control-controlled" relationship. Communication lines 19 are drawn as dotted lines. The example is shown in a "first" controller 16 of the AC-DC converter and converter 4 and a "second" controller of the converter 16 and AC-DC converter 4 in the left half of figs. 3a, 3b. Different stages of the transfer are

20 schematically shown in fig. 3c.

According to 20 (see Fig. 3c) before a handover, the first controller of the converter is the functional controller of the first converter while the second controller of the converter is the functional controller of the second converter. According to figs. 1 and 2, the first controller is associated with the first converter and the second controller is associated with the second converter. In the event that (for example) the second controller 25 is damaged in 21 (mixed line in Fig. 3b), the first controller assumes the functional control of the second converter. This occurs without the first controller losing any control functionality over the first converter. As a result of the fault, the second converter is no longer controlled. Information about the fault is provided by the communication lines 19, for example by a broadcast signal sent by the second controller or by setting the shared memory to a value indicating the error status (if it is still

30 able to communicate). This information can also be provided by the fact that the second controller no longer shows any sign of life.

This information is received (by all controllers and especially) by the controllers 17 of the power dissipation unit associated with the power path of the second converter. At 22, this controller 17 will begin (self-acting) to control the switches 14 to connect the power dissipation unit 6 to the

35 DC link to dissipate the power of the DC side of the second converter. In another example, the power (from the source side) that had to be managed by the second converter dissipates.

In addition, the information about the fault is received by the first controller, which also analyzes (continuously) all the information received about the system 1. As the first controller controls only the first individual element at that moment of time, it is in principle capable of controlling an additional element.

40 Thus, the first controller begins the handover (or "takeover", since the second controller is not actively involved due to the fault) with the disconnection of the second converter from the AC link 8 on the source side at 22 Thus, no more power will be guided to the second uncontrolled converter. To transfer the element, the first controller also disconnects the second controller of the second converter at 22, for example by changing the pointers of the control process of the second controller to a NIL value (i.e., pointing

45 to nowhere), or physically disconnecting signal lines 18 between the second controller and the second converter using semiconductor switches.

Next, the second converter is connected to the first controller at 23, for example by physically switching the connection signal lines 18 or by duplicating the control (program) commands for the first converter to the second converter (in the case of controlling two converters using the first controller to

50 unison), or by connecting a second controller unit (hitherto inactive) from the first controller to the second converter. Thus, the functionality of the second converter is transferred to the first controller. Next, the power dissipation units 6 are disconnected by the controller 17 at 23 and the AC link 8 on the source side is connected to the second controller.

Finally, at 24, the first controller controls both the first and the second element, while the second

55 controller does not control anything, as it has failed. This ensures that the power transfer system 1, and therefore the wind turbine, will not be disconnected from the network in the event of a controller failure.

For example, this applies to any of two controllers of the converter 16 as well as to any of two controllers 17 of the power dissipation unit that control two converters 4 and / or 5 and two control units.

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power dissipation 6, respectively. This also applies to source-load management controllers 15 and sources 2 and loads 3, respectively.

In another embodiment, additionally or alternatively, a controller in good condition (without any fault status) is controlled by another controller. Thus, a single controller is controlling two elements in a normal 5 mode. Thus, if (later) a system failure arises, the effect of the failure is mitigated, the power flow to the load is optimized and / or the mechanical stability of the generator is maintained.

Fig. 4: controller communication

Fig. 4 shows the information that is being shared between different types of controllers. Each circle represents all 15-17 controllers of the same type. In this embodiment, information 10 is exchanged by broadcasting to all controllers of all types with individual controllers that intelligently extract the information they need for functional decision making. As mentioned earlier, communication between controllers is carried out by means of a shared memory and communication between processes (in some alternative embodiments, the sending controller is directed to a specific receiving controller. In some embodiments, this communication between controllers takes

15 conducted through physical communications links).

The solid lines represent the exchange of event information 18, for example about status and error; dotted lines represent the exchange of signal information 19, for example about system parameters.

Source-load management controllers 15 provide event information to all others.

20 controllers, for example about the status and / or errors of the sources 2, the loads 3 and / or the controllers themselves 15, or about global system commands, for example start, shutdown, power generation. In addition, they provide real-time signal information to all other controllers, for example about desired individual power set points of converters, available source power, load power consumption.

25 The controllers of converter 16 provide event information to all other controllers, for example about status and / or error of converters 4, 5 and / or of the controllers themselves 16. In addition, they provide real-time signal information to all other controllers, for example about the power ratio to be converted and / or the energy stored in links 7,8.

Controllers 17 of the power dissipation unit provide event information to all others

30 controllers, for example about the status and / or error of the power dissipation units 6 and / or the controllers themselves 17. In addition, they provide real-time signal information to all other controllers, for example about the quantity and / or power ratio to be dissipated and / or good working conditions of the power dissipation elements, for example, temperature.

The shared information allows each controller to make functional decisions independently in order

35 to achieve the desired system behavior in both independent and shared modes described above.

Claims (10)

1. A system comprising a wind turbine, an electric generator, an electric power transfer system (1) and an electric supply network, in which the power transfer system (1) is arranged to transfer electric power from the generator to a power supply network; 5 in which the power transfer system (1) comprises at least two electrical elements (2-6) and at least two controllers (15-17), each arranged to control at least one element (2-6); wherein at least one controller (15-17) is arranged to control only one of the elements (2-6) as well as at least two of the elements (2-6); Y the arrangement of controllers allows a first element (2-6) to be controlled by a first 10 controller (15-17) and a second element (2-6) is controlled by a second controller (15-17), as well as the first and second element (2-6) being controlled by the first controller (15 -17) while the first or second element (2-6) is not controlled by the second controller (15-17). 2. The system of claim 1, wherein at least two of the elements (4, 5, 6) are electrical power converters and at least two of the controllers are converter controllers (16). The system of claim 1 or 2, wherein the power transfer system (1) comprises at least one AC / DC converter (4) and at least one DC / AC converter (5) as elements and comprises at least one DC link (7) arranged to couple at least one AC / DC converter (4) and at least one DC / AC converter (5). 4. The system of any one of claims 1 to 3, wherein at least two of the elements are 20 power dissipation units (6) and at least two of the controllers are controllers (17) of the power dissipation unit. 5. The system of any one of claims 1 to 4, wherein at least one of the generator and the power supply network provides as elements at least two sources (2) and at least two charges (3), respectively, and in which at least two of the controllers are source management controllers 25 load (15), each arranged to monitor at least one of the source (2) and the load (3).

6.

The system of any one of claims 1 to 5, wherein at least the first controller (15-17) is arranged to uniformly control at least two elements (2-6).

7.

The system of any one of claims 1 to 6, wherein at least the first controller (15-17) is arranged to control at least two elements (2-6) independently.

The system of any one of claims 1 to 7, wherein at least the second controller (15-17) is arranged to generate a signal for at least the first controller (15-17) to provide at least one of information about himself and information about at least one of the elements (2-6) controlled by him. 9. The system of any one of claims 1 to 8, wherein at least the second controller (15-17) 35 is arranged to generate a broadcasting signal to provide at least one of information about itself and information about at least one of the elements (2-6) controlled by it. 10. The system of any one of claims 1 to 9, wherein at least the first controller (15-17) is arranged to decide in isolation whether to control only one element (2-6) or control at least two elements ( 2-6) at the same time. The system of any one of claims 1 to 10, wherein the power transfer system (1) comprises at least one electric power converter (4, 5), at least one converter controller (16) and at least one controller (17) of the power dissipation unit, in which the converter controller (16) is arranged to provide at least one of information about itself and information about the converter (4, 5) to the controller (17) of the power dissipation unit. 45 12. A method for controlling a control arrangement of an electric power transfer system (1) of a wind turbine, in which the wind turbine comprises an electric generator and is connected to a power supply network, and in the that the power transfer system (1) is arranged to transfer electrical power from the generator to the power supply network; wherein the power transfer system (1) comprises at least two elements (2-6) and at least two controllers (15-17), each arranged to control at least one element (2-6); in which at least one controller (15-17) is arranged to control only one of the elements as well as the 14 minus two of the elements (2-6); the procedure comprising: switching between controlling a first element (2-6) with a first controller (15-17) and a second element (2-6) with a 5 second controller (15-17) and control the first and second element (2-6) with the first controller (15-17) while the first or second element (2-6) is not controlled with the second controller ( 15-17).

13.

The method of claim 12, wherein the switch is triggered by a fault condition.

14.

The method of claim 12 or 13, wherein the generator and the power supply network

10 provide at least one source (2) and one load (3), respectively; wherein the power transfer system (1) comprises at least two electric power converters (4, 5) and at least one power dissipation unit (6) as elements, at least two converter controllers (16), at least one controller (17) of the power dissipation unit and a power path arranged to transfer electrical power to the load (3); 15 comprising the procedure: controlling a first converter (4, 5) with a first converter controller (16) and a second converter (4, 5) with a second converter controller (16) with both converters (4, 5) being connected to the power path , and, in response to a fault condition caused by the second controller (16), 20 disconnect the second converter (4, 5) from the power path and connect it to the power dissipation unit (6) controlled by the controller (17) of the power dissipation unit, transfer the second converter (4, 5) to the first converter controller (16), disconnect the second converter (4, 5) from the power dissipation unit (6) and reconnect the second converter (4, 5) to the power path. 25 fifteen